Humus Status of Different Soil Types in Bulgaria

Abstract

Values of a number of diagnostic humus parameters were established to assess the humus status of various soils in Bulgaria. In summary, the assessment of soils can be represented as follows: climate, plant and other conditions in large part of the country, especially in lowland and hilly part, where is concentrated cultivated land fund, are favorable for the formation of qualitative humus. However the amount of humus, in topsoil has decreased, but the quality has not changed significantly. Humus of humic and fulvic-humic type predominates. Humus is enriched to a great extend with nitrogen. All humic acids are bounded with calcium and pH of the medium is neutral. They have a high optical density. Almost in all soils humification of organic matter is high. Only in some soils, humus condition can be assessed as unsatisfactory — pseudopodzolic and saline soils.